Transmission belts of the kind mentioned which transmit drive forces by form-lock engagement from a drive gear are just as well known as flat drive belts which are passed under tension around smooth drive and return pulleys, whereby the drive force is transmitted from the driven pulley to the belt by force or friction lock. It is known that the force to be transmitted can be increased by devising the transmission belt so that it has teeth which protrude from one side of a supporting belt and using a drive pulley provided with complementary teeth along its periphery. Likewise known are transmission belts which cooperate both in force- and friction-lock engagement with the drive wheel (belt pulley). Known flat belts are formed with spaced breakthroughs which are engaged by corresponding pins projecting from the periphery of the belt pulley. Another known transmission belt is corrugated or toothed and runs around spaced apart gears whose width corresponds to that of the transmission belt and of which one is a driven gear. This belt may have breakthroughs between individual wave-shaped deformations to permit drive forces to be introduced or branched off.
Other similar drive means are chain drives comprising suitable sprocket gears, others comprising steel cables which are passed around grooved pulleys, or rope transmissions with balls or the like fastened on the ropes at certain spacings for engagement in complementary, widened sections of grooves formed in the drive pulleys. All these measures are intended to warrant that the drive force is transmitted in form lock. The fields of application of these drive means partly differ from one another, while they overlap in other respects. The strengths and weaknesses, or the advantages and disadvantages, of all these drives are well known. Those skilled in the art likewise dispose of sufficient knowledge concerning materials which are suitable for flat belts and V belts.